All-laser-micromachining of ridge waveguides in LiNbO3 crystal for mid-infrared band applications

Abstract

The femtosecond laser micromachining of transparent optical materials offers a powerful and feasible solution to fabricate versatile photonic components towards diverse applications. In this work, we report on a new design and fabrication of ridge waveguides in LiNbO3 crystal operating at the mid-infrared (MIR) band by all-femtosecond-laser microfabrication. The ridges consist of laser-ablated sidewalls and laser-written bottom low-index cladding tracks, which are constructed for horizontal and longitudinal light confinement, respectively. The ridge waveguides are found to support good guidance at wavelength of 4 μm. By applying this configuration, Y-branch waveguiding structures (1 × 2 beam splitters) have been produced, which reach splitting ratios of ∼1:1 at 4 μm. This work paves a simple and feasible way to construct novel ridge waveguide devices in dielectrics through all-femtosecond-laser micro-processing.

Femtosecond laser direct writing of flexibly configured waveguide geometries in optical crystals: fabrication and application

“…Likewise, the optical barriers for providing vertical light confinement can be also provided by FsLDW induced low-index tracks. Together with the laser ablated grooves, surface ridge waveguide splitters in LiNbO 3 have been demonstrated 60 . Most recently, by combining chemical etching with femtosecond laser micromachining, the etching rate of nanopore lattices in YAG and sapphire can be enhanced by more than five orders of magnitude, enabling rapid definition of arbitrary 3D nanostructures with size of 100 nm in crystals 61 .…”

Ultrafast Laser Inscription of Buried Waveguides in W-TCP Bioactive Eutectic Glasses

“…Since the first report on femtosecond laser written waveguides in glass by Davis et al [22], different types of integrated optical waveguides have been produced in a great diversity of transparent materials such as glasses, crystals, polycrystalline ceramics and polymers [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67].…”

“…Finally, in Type IV, waveguide also referred as ridge waveguides, the ultra-high intensity achieved by the femtosecond laser pulses is used to ablate the surface to produce ridge waveguides on planar waveguide substrates obtained by other methods. Therefore, the guiding features strongly depend on the planar waveguide substrate [63][64][65][66][67].…”

Refractive Indexes and Spectroscopic Properties to Design Er3+-Doped SiO2–Ta2O5 Films as Multifunctional Planar Waveguide Platforms for Optical Sensors and Amplifiers

“… 1 For instance, their use as a platform for optical sensors is one of the great potential applications for waveguides. 2 − 5 Nowadays, most of the wearable augmented reality display devices operate using waveguide technology, of which some are commercial products. However, mass production has been already limited by cost and performance in many cases.…”